The present invention relates to electronic devices, and, more particularly, to mobile electronic devices that can be used by persons with a hearing impairment and methods of operating the same.
The gradual loss of hearing that occurs as a person ages is a relatively common condition. An estimated one-third of Americans older than age 60 and one-half of those older than age 75 have a hearing impairment. Over time, noise may contribute to hearing loss by damaging the cochlea, which is a part of the inner ear. Other factors, such as blockage due to earwax, may reduce the ability of the ear to detect certain sounds or frequencies. Although inner ear damage may not be reversed, a person experiencing hearing loss may be fitted with a hearing aid, which may improve the person's hearing.
It may be desirable for mobile electronic devices, such as mobile terminals, to be hearing aid compatible. In fact, the hearing aid compatibility of certain devices has been mandated in the United States by the U.S. Federal Communications Commission (FCC). One problem experienced when using a hearing aid in conjunction with other devices is that the microphone inside a hearing aid may be susceptible to noise from the surrounding environment. For example, it may be difficult for a hearing aid user to hear an audio signal broadcast from a telephone handset speaker, due to the background and/or environmental noise that is also picked-up by the hearing aid microphone.
Accordingly, hearing aids have been developed that provide alternatives to conventional acoustic coupling to the hearing aid microphone (i.e., by placing the device broadcasting the audio signal adjacent to the hearing aid) for receiving an audio signal from other devices. For example, many hearing aids currently include a telecoil, also referred to as a “T-coil”. The telecoil is an induction coil inside the hearing aid that converts magnetic energy to electrical energy. When a hearing aid is switched to the “T” position, the hearing aid microphone may be deactivated, and the telecoil may permit a hearing aid user to inductively couple other devices to the hearing aid. For example, the telecoil may pick-up the audio signal magnetic field emitted by a voice coil in a conventional landline telephone handset speaker, and may transform the magnetic field into a boosted audio signal that can be heard by the hearing aid user. As such, environmental and/or background noise may not transmitted to the hearing aid user when the telecoil is used.
However, when used with a mobile terminal, such as a digital cellular phone, baseband interference from the phone's electronics and radio frequency (RF) interference due to emissions from the phone's antenna may result in magnetic field noise. This magnetic field noise may be picked-up by the telecoil and transmitted to the hearing aid user. For example, in TDMA-type air interfaces, the signal-to-noise ratio for telecoil inductive coupling may be poor. As such, telecoil usability may suffer, which may impede the use of digital cellular phones by hearing aid users.